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SQL Design Patterns (2010)

(vadimtropashko.wordpress.com)
149 points mci | 1 comments | 27 Aug 25 04:59 UTC | HN request time: 0s | source
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potatoproduct ◴[30 Aug 25 19:11 UTC] No.45077193[source]▶
Not ashamed to admit that I never really thought about the distinct operator 'being redundant' as its essentially just a group by.
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morkalork ◴[30 Aug 25 19:55 UTC] No.45077523[source]▶
distinct has always felt like a query smell to me. Too many junior analysts abusing it because they don't know the schema well and are over-joining entities
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1. ryanjshaw ◴[30 Aug 25 21:45 UTC] No.45078258[source]▶
Sometimes the number of joins is fine but they don’t understand the data properly and should be spending more time understanding why multiple rows are being returned when they expect one (eg they need to filter on an additional field).

I wish SQL had a strict mode syntax that forces you to use something like `select one` (like LINQ’s Single()) or `select many` to catch these kinds of bugs.